GoProxli - A simple Go Proxy Server

A simple HTTP proxy server written in Go, designed to forward requests to a specified target server while injecting custom headers. This proxy can be used to simulate scenarios such as traffic redirection through API gateways or the addition of headers for testing purposes.

Features

• HTTP Proxy: Forward incoming requests to a specified target server.
• Custom Header Injection: Modify or add headers to outgoing requests.
• Cross-Platform Support: Build and run on Linux, macOS, and Windows.
• Dynamic Target Configuration: Specify the target server via command-line arguments.
• Extensible: Easily extendable to add more features such as request/response logging, caching, etc.

Use Cases

• Simulate API Gateways: Use the proxy to simulate traffic routing through an API gateway, where headers (such as authentication tokens or client information) are injected into each request.
• Testing and Debugging: Proxy requests to an API and inject headers like X-Forwarded-For or Authorization to test how the backend handles different headers.
• Traffic Monitoring: Modify the proxy to add logging or metrics to monitor traffic passing through the system.

Getting Started

Prerequisites

• Go 1.20+ installed on your machine.

Installation

1. Clone this repository:

git clone https://github.com/osuritz/go-proxli.git
cd go-proxli

2. Build and run during development

go run ./src -target <server>

3. Build the Go binary:

go build -o go-proxli ./src/

4. Run the proxy server:

./go-proxli -target http://destination-server.com -port 8080

Replace http://destination-server.com with the actual server URL you want to proxy requests to. The proxy will listen on localhost:8080 by default (you can change the port via the -port flag).

Usage

./go-proxli -target http://your-target-server.com -port 8080

This command will start the proxy server on port 8080, forwarding requests to the specified target server (http://your-target-server.com).

Injecting Custom Headers

To simulate traffic routing through an API gateway, you can modify the ProxyHandler function in proxy.go to inject custom headers. Here's an example of how you can add a header like X-Proxy-By to every request:

// Add a custom header before forwarding the request
req.Header.Add("X-Proxy-By", "GoProxli Server")

Simply edit the code in src/proxy.go to add more headers as needed.

Command-Line Flags

• -target: (Required) The URL of the target server to forward requests to.
• -port: (Optional) The port to run the proxy server on. Default is 8080.

Example

./go-proxli -target http://example.com -port 9090

This will start the proxy server on port 9090 and forward all requests to http://example.com.

Development

Modifying the Proxy

You can extend or modify the proxy server by editing the src/proxy.go file. For example, you can:

• Add more custom headers.
• Implement request/response logging.
• Add support for TLS/HTTPS connections.

Testing

You can test the proxy server locally using curl or any HTTP client:

curl -I http://localhost:8080/some-endpoint

License

This project is licensed under the MIT License. See the LICENSE file for details.

Contributing

Feel free to open issues or submit pull requests. Contributions are always welcome!